Combustor with adjustable swirler and a combustion system

ABSTRACT

A combustor having an ion transport membrane therein and an adjustable swirler, which is mechanically connected at an inlet of a combustion zone of the combustor; a combustion system comprising the combustor, a feedback control system adapted to adjust swirler blades of the combustor based on a compositional variation of a fuel stream, and a plurality of feedback control systems to control operational variables within the combustor for an efficient oxy-combustion; and a process for combusting a fuel stream via the combustion system. Various embodiments of the combustor, the combustion system, and the process for combusting the fuel stream are disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on, and claims the benefit of priority to,provisional application No. 62/298,263 filed Feb. 22, 2016, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to a combustor having an ion transportmembrane therein to produce molecular oxygen, and an adjustable swirler,which is mechanically connected at an inlet of a combustion zone of thecombustor. Furthermore, the present disclosure relates to a combustionsystem and a process for combusting a fuel stream via the combustionsystem.

Description of the Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Syngas is widely used as a source of energy for industrial applications.A syngas stream can be produced via gasification of biofuels and fossilfuels (e.g. coal and heavy oil), or via reforming (e.g. catalyticreforming) of methane. Producing syngas via methane reforming powered bysolar energy (i.e. solar methane reforming) can be a means for storingsolar energy. Furthermore, using syngas as a fuel is in line withenvironmental policies adapted to reduce the carbon dioxide (CO₂)emission rates. However, using syngas produced via solar methanereforming is challenging. For example, solar radiation variessignificantly throughout a year, or even throughout a day. Thesevariations result in a considerable effect in the conversion rates ofthe fossil fuels and the composition of the produced syngas. A change inthe composition of the syngas may substantially affect the thermalenergy (or Wobbe index) of the syngas, thus resulting in a change inheat release rate, a change in emission rate, and a change in stabilityof the combustor.

In order to efficiently extract the energy of a syngas stream producedvia solar methane reforming, an adjustable system is needed tocontinuously adjust itself based on the variations of the fuelcomposition (i.e. syngas). On the other hand, the system should includea controller to stabilize the combustion conditions. The controlleradjusts the system based on the variations in the fuel composition ofthe syngas stream.

To reduce the greenhouse gas emissions, several approaches have beenadapted to effectively capture carbon dioxide. These approaches areeither post-combustion, pre-combustion, or oxy-combustion. The prior artreference U.S. Pat. No. 7,927,568 B2 describes a capturing procedurethat optimizes the CO₂ cooling duty and compression power. Researchersare more interested in oxy-combustion approaches as a more promising wayof recovering and capturing carbon dioxide from flue gases. In addition,oxy-combustion also serves as means of addressing other environmentalconcerns such as elimination of NOx emissions. The oxy-combustioninvolves burning a fuel in pure oxygen or a mixture of oxygen and carbondioxide. Separation of oxygen from an oxygen-containing mixture (e.g.air) can be obtained, for example, via an ion transport membrane. Theion transport membrane provides a selective permeation of oxygen. Theprior art reference US005534471A describes a superior oxygen separationrate (i.e. oxygen flux through the membrane) via a surface catalyzed iontransport membrane. Accordingly, an air stream was maintained at atemperature in the range of 700° C. and 1100° C., for an effectivepermeation of oxygen. The prior art reference U.S. Pat. No. 8,114,193 B2demonstrated an effective oxygen separation from air using a pluralityof ion transport membrane (ITM) modules that are arranged in series in apressure vessel. To achieve the permeation temperature, the membrane mayhave been thermally coupled to the combustor. The US patent application20140216046 A1 described an integration of ion transport membrane (ITM)oxygen separation systems with a gas turbine combustor to reduce aNO_(x) emission during the operation of the combustor. The integrationis such that oxygen directly permeates into the combustion zone of thecombustor, while a non-permeated portion (oxygen depleted air) mayeither be premixed with the fuel and air, may be used as a diluent tocontrol a NO_(x) emission rate, or may be used as a coolant forcombustor liner cooling. In another US patent application US2014/0174329 Al a means of controlling reaction temperatures of an iontransport membrane reactor is described via a thermally conductiveplate. Furthermore, the patent reference U.S. Pat. No. 6,565,632 B1related to a structural support disposed within a tubular ion transportmembrane to prevent inward collapse of the membrane under excessivepressures. Additionally, the prior art reference EP 2,613,086 A2disclosed a variable swirler assembly comprising a fixed and a movableblade to extend the operating range for gas turbines running on variousfuels. Accordingly, the blade angles have to be set before running theturbine to give enough safety margins for a reliable operation. Thesystem, as described in this reference, does not continuously adjustitself based on the variations of syngas composition. Furthermore, thesystem does not appear to mention the use of an ITM to produce pureoxygen for oxy-combusting a fuel.

The oxy combustion of syngas obtain from solar methane reformingprovides a new route for an emission-free system. The emissions fromsuch systems are mainly carbon dioxide and water vapor. The water vaporcan be condensed and a relatively pure carbon dioxide can be captured.As a result, the costs associated with post-combustion or pre-combustiontreatments to capture CO₂ are either eliminated or at leastsubstantially reduced. Having an ITM integrated to a combustor providesa continuous supply of pure oxygen for an oxy-combustion process. Theoxy-combustion process is generally carried out at a relatively hightemperature, and thus produces high temperature products. As a result, arecycle stream may be needed (e.g. a portion of the flue/exhaust gas) tobe mixed with the fuel stream to keep the temperature of the combustionwithin an allowable temperature range.

The main challenge in the design of such systems is the adaptability ofthe system to compositional changes of the fuel. In addition, issuessuch as controlling the flow rate of the fuel to be in thestoichiometric ranges with the permeated oxygen, or controlling the flowrate of the recycling exhaust gas based on its temperature need to beaddressed to avoid major thermal and/or mechanical stresses on thesystem. While an integration of an ITM combustor to a gas turbine hasbeen disclosed in the prior art, an ITM-combustor having an adjustableswirler, which is connected to a feedback control system, for anefficient oxy-combustion does not appear to be disclosed previously.

In view of the forgoing, one objective of the present disclosure relatesto a combustor having an ion transport membrane therein to producemolecular oxygen, and an adjustable swirler, which is mechanicallyconnected at an inlet of a combustion zone of the combustor.Furthermore, the present disclosure relates to a combustion systemhaving the combustor, a feedback control system adapted to adjust theswirler blades based on the compositional variations of a fuel stream,and a plurality of feedback control systems to control operationalvariables (i.e. temperature, flow rate, pressure, etc.) within thecombustor for an efficient oxy-combustion. The present disclosure alsorelates to a process for combusting a fuel stream via the combustionsystem.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect, the present disclosure relates to acombustor, including i) a cylindrical vessel with an internal cavity,ii) an ion transport membrane that divides the internal cavity of saidvessel into a first and a second concentric cylindrical zone, whereinthe first concentric cylindrical zone is a feed zone and the secondconcentric cylindrical zone is a combustion zone, iii) a first inlet anda first outlet located in the feed zone, and a second inlet and a secondoutlet located in the combustion zone, iv) a swirler that is connectedto the second inlet, wherein the swirler has adjustable blades withadjustable angles.

In one embodiment, the swirler comprises a plurality of blades extendingradially from a shaft, wherein each blade has a longitudinal axis and anangle of the longitudinal axis of each blade is adjustable relative to alongitudinal axis of the shaft.

In one embodiment, the angle of the longitudinal axis of each blade isadjustable in the range of 0 to 85 degrees relative to the longitudinalaxis of the shaft.

In one embodiment, the combustor further includes i) a third concentriccylindrical zone which is sandwiched between the first and the secondconcentric cylindrical zones, defining a sweep zone, ii) a third inletand a third outlet located in the sweep zone.

According to a second aspect the present disclosure relates to acombustion system, including i) the combustor of in accordance with thefirst aspect, ii) an oxygen supplier located upstream of and fluidlyconnected to the first inlet via a feed line for supplying anoxygen-containing stream, iii) a fuel supplier located upstream of andfluidly connected to the second inlet via a fuel line for supplying afuel stream.

In one embodiment, the combustion system further includes an expanderlocated downstream of and fluidly connected to the second outlet via anexhaust line for expanding an exhaust stream to generate power.

In one embodiment, the combustion system further includes a swirlercontrol unit, including a) a first gas analyzer disposed on the fuelline configured to determine a composition of the fuel stream, b) asecond gas analyzer disposed on the exhaust line configured to determinea composition of the exhaust stream, c) an actuator connected to theadjustable blades of the swirler configured to adjust an angle of theadjustable blades, d) a processor that is configured to receive a firstsignal from the first gas analyzer and a second signal from the secondgas analyzer, and to transmit a first output signal to the actuator,wherein the swirler control unit is configured to adjust an angle of theadjustable blades based on the composition of the fuel stream and theexhaust stream.

In one embodiment, the combustion system further includes a flow controlunit, including a) a first gas analyzer disposed on the fuel lineconfigured to determine a composition of the fuel stream, b) a flowmeterdisposed on the fuel line configured to determine a volumetric flow rateof the fuel stream, c) a first control valve disposed on the feed lineconfigured to control a volumetric flow rate of the oxygen-containingstream, d) a flow controller that is configured to receive a firstsignal from the first gas analyzer and a flow rate signal from theflowmeter, and to transmit a second output signal to the first controlvalve, wherein the flow control unit is configured to control thevolumetric flow rate of the oxygen-containing stream based on acomposition and volumetric flow rate of the fuel stream.

In one embodiment, the combustion system further includes i) a recycleline that fluidly connects the exhaust line to the fuel line, ii) atemperature control unit, including a) a temperature sensor disposed onthe exhaust line configured to determine a temperature of the exhauststream, b) a second control valve disposed on the recycle lineconfigured to control a volumetric flow rate of the exhaust stream, c) atemperature controller configured to receive a temperature signal fromthe temperature sensor, and to transmit a third output signal to thesecond control valve, wherein the temperature control unit is configuredto control the temperature of the fuel stream based on the temperatureof the exhaust stream.

In one embodiment, the combustion system further includes a mixerlocated upstream of the combustor and fluidly connected to the fuel lineand the recycle line configured to mix the fuel stream with the exhauststream.

In one embodiment, the combustion system further includes i) anoxygen-depleted line fluidly connected to the first outlet, ii) aprimary heat exchanger disposed on the recycle line and fluidlyconnected to the oxygen-depleted line, wherein the primary heatexchanger is located downstream of the first outlet and upstream of themixer, and is configured to heat exchange the exhaust stream with anoxygen-depleted stream that egresses the first outlet.

In one embodiment, the combustion system further includes i) anoxygen-depleted line fluidly connected to the first outlet, ii) asecondary heat exchanger disposed on the feed line and fluidly connectedto the oxygen-depleted line, wherein the secondary heat exchanger islocated upstream of the first inlet and downstream of the first outlet,and is configured to heat exchange the oxygen-containing stream with anoxygen-depleted stream that egresses the first outlet.

In one embodiment, the combustion system further includes a condenserlocated downstream of and fluidly connected to the expander via theexhaust line, configured to separate a liquid phase from the exhauststream.

In one embodiment, the combustor of the combustion system furtherincludes a) a third concentric cylindrical zone sandwiched between thefirst and the second concentric cylindrical zones, defining a sweepzone, b) a third inlet and a third outlet located in the sweep zone. Inone embodiment, the combustion system further includes a recycle linethat fluidly connects the exhaust line to the third inlet.

According to a third aspect the present disclosure relates to a processfor combusting a fuel stream, involving i) combusting the fuel streamwith molecular oxygen in the combustion zone of the combustor, whichincludes a sweep zone, to form an exhaust stream comprising water vaporand carbon dioxide, ii) delivering an oxygen-containing stream to thefirst inlet of the combustor, wherein molecular oxygen present in theoxygen-containing stream is transported to the sweep zone through theion transport membrane, iii) flowing a portion of the exhaust streaminto the third inlet of the combustor to sweep the molecular oxygen awayfrom the sweep zone and to form an oxygen-enriched stream, iv) mixingthe oxygen-enriched stream with the fuel stream in a mixer to form acombustion mixture, v) delivering the combustion mixture to the secondinlet of the combustor, wherein the combustion mixture is expandedand/or agitated in the combustion zone via the swirler and is combustedto form the exhaust stream, and repeating the flowing, the mixing, andthe delivering.

In one embodiment, the fuel stream is a syngas stream.

In one embodiment, the process further involves expanding the exhauststream in an expander to generate power.

In one embodiment, the process further involves adjusting an angle ofeach blade of the swirler based on a composition of the combustionmixture.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1A is a process flow diagram of a combustion system having aprimary heat exchanger configured to heat exchange an exhaust streamwith an oxygen-depleted stream that egresses a first outlet of acombustor.

FIG. 1B is a process flow diagram of the combustion system having asecondary heat exchanger configured to heat exchange anoxygen-containing stream with an oxygen-depleted stream that egressesthe first outlet.

FIG. 1C is a process flow diagram of the combustion system, wherein thecombustor further includes a sweep zone.

FIG. 2A illustrates an axial cross-section of the combustor at a firstend.

FIG. 2B is a magnified illustration of an ion transport membrane, and amechanism of oxygen permeation therethrough.

FIG. 3A illustrates an adjustable swirler in a perspective view.

FIG. 3B illustrates the adjustable swirler in a side view.

FIG. 3C illustrates an adjustable swirler having a shroud.

FIG. 4A represents a stability limit of a flame for two combustionmixtures, i.e. CH₄ only, and CH₄/H₂, at a swirl angle of 30°.

FIG. 4B represents a stability limit of a flame for two combustionmixtures, i.e. CH₄ only, and CH₄/H₂, at a swirl angle of 45°.

FIG. 4C represents a stability limit of a flame for two combustionmixtures, i.e. CH₄ only, and CH₄/H₂, at a swirl angle of 55°.

FIG. 5A represents the stability limit of a flame for a combustionmixture having CH₄ only, at various swirl angles.

FIG. 5B represents the stability limit of a flame for a combustionmixture having CH₄/H₂, at various swirl angles.

FIG. 6 represents an experimental and a predicted minimum swirl angle ofthe adjustable swirler under various operating conditions.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views.

According to a first aspect the present disclosure relates to acombustor 112, including a cylindrical vessel with an internal cavity.

The term “combustor” refers to an apparatus or a device, whereincombustion takes place. The cylindrical vessel of the combustor 112refers to a container having a cylindrical internal cavity that isconfigured to hold a gaseous mixture at elevated temperatures andpressures. For example, in a preferred embodiment, the vessel isconfigured to hold a gaseous mixture at a temperature in the range of800-1,500° C., preferably 800-1,200° C., more preferably 800-1,000° C.,and a pressure in the range of 1-100 atm, preferably 1-50 atm, morepreferably 10-50 atm. The cylindrical vessel may be made of alumina,quartz, stainless steel, nickel steel, chromium steel, aluminum,aluminum alloy, copper and copper alloys, titanium, and the like,although the materials used to construct the cylindrical vessel are notmeant to be limiting and various other materials may also be used. Inone embodiment, the cylindrical vessel is made of a metal or an alloye.g. stainless steel, nickel steel, chromium steel, copper alloys,titanium, and the like, and a lining of a ceramic material (e.g.alumina), quartz, and/or a Pyrex® is used to minimize internal surfaceoxidation of the cylindrical vessel. However, in a preferred embodiment,the cylindrical vessel is made of a high-temperature duty ceramiccomposite that can endure a temperature of up to 1,500° C., preferablyup to 2,000° C., more preferably up to 2,500° C. The cylindrical vesselmay have an internal volume in the range of 10-10,000 L, or preferably100-5,000 L, or preferably 500-3,000 L, or preferably 1,000-2,000 L. Thecylindrical vessel may preferably have a longitudinal axis parallel to aground surface (as shown in FIG. 1A, 1B, and 1C). The cylindrical vesselmay be a portion of a pipe.

The combustor 112 further includes an ion transport membrane 210 thatdivides the internal cavity of said vessel into a first and a secondconcentric cylindrical zone, wherein the first concentric cylindricalzone is a feed zone 110 and the second concentric cylindrical zone is acombustion zone 108. For example, in one embodiment, the cylindricalvessel is horizontally oriented and the ion transport membrane 210disposed therein with a longitudinal axis, which is substantiallyparallel to a longitudinal axis of the cylindrical vessel.

The ion transport membrane (ITM), used in the combustor 112, functionsto separate oxygen from air or other oxygen-containing gaseous mixturesby transporting oxide ions (i.e. O²⁻) through a material that is capableof conducting oxide ions and electrons at elevated temperatures. When apartial pressure difference of oxygen is applied on opposite sides ofsuch a membrane, oxygen molecules ionize on one surface of the membraneand emerge on an opposite side of the membrane as oxide ions. Then theoxide ions (i.e. O²⁻) recombine into molecular oxygen (i.e. O₂). Freeelectrons resulting from the combination of oxide ions will betransported back through the membrane to ionize another oxygen molecule(this concept is depicted in FIG. 2B).

The ion transport membrane 210 is a semi-permeable membrane that allowspassage of oxide ions (i.e. O²⁻) from the feed zone 110 to thecombustion zone 108. The semi-permeable membrane refers to a membranethat allows molecules or ions (in this case oxide ions) with a certainStokes radius to pass through it by diffusion. Stokes radius of asubstance in a membrane refers to the radius of a hard sphere thatdiffuses at the same rate as that substance through the membrane.Diffusion refers to a passage of the oxide ions through the ITM, anddiffusivity is a passage rate of the oxide ions, which is determined bya differential in oxygen partial pressure on both sides of the ITM aswell as a volume fraction (or a number) of oxide ion vacancies presentin the ITM.

As used herein, the feed zone 110 of the combustor 112 refers to a spaceinside the vessel that is configured to hold an oxygen-containinggaseous mixture. Similarly, the combustion zone 108 (or permeate zone)refers to a space inside the vessel wherein a fuel stream 104 s (e.g. asyngas stream) is combusted. The feed zone 110 and the combustion zone108 are separated by the ITM 210. When an oxygen molecule present in anoxygen-containing gaseous mixture is contacted with the feed zone 110 ofthe ITM, the oxygen molecule may be reduced and an oxide ion (i.e. O²⁻)may be formed. The oxide ions may be transported through the iontransport membrane and may be combined into molecular oxygen 114 (i.e.O₂) on the combustion zone 108 of the ion transport membrane. A fuelstream 104 s (e.g. a syngas stream) may be combusted in the presence ofthe molecular oxygen 114 in the combustion zone 108 of the combustor112.

The ITM 210 may have a composition with a general formulaA_(x)A′_(x′)B_(y)B′_(y′)O_(3-z), wherein each of A and A′ is selectedfrom the group consisting of Sr, Ba, La, and Ca, and each of B and B′ isselected from the group consisting of Fe, Co, Cr, Ti, Nb, Mn, and Ga.Further, each of x, x′, y, and y′ in the general formula of the iontransport membrane has a value between 0 and 1, such that x+x′=1 andy+y′=1. Also, z is a number that varies to maintain electro-neutralityof the ITM. For example, in some embodiments, the ITM is aperovskite-type ceramic having a composition ofBa_(u)Bi_(w)Co_(x)Fe_(y)O_(3−δ), Ba_(u)Co_(w)Fe_(x)Nb_(y)O_(3−δ),Ba_(u)Fe_(x)Nb_(y)O_(3−δ), Ba_(w)Ce_(x)Fe_(y)O_(3−δ),Ba_(u)Sr_(w)Co_(x)Fe_(y)O_(3−δ), Ba_(u)Ti_(w)Co_(x)Fe_(y)O_(3−δ),Ca_(u)La_(w)Fe_(x)Co_(y)O_(3−δ), Sr_(u)Ca_(w)Mn_(x)Fe_(y)O_(3−δ),Sr_(u)Co_(w)F e_(y)O_(3−δ), La₂NiO_(4+δ), La_(w)Ca_(x)Fe_(y)O_(3−δ),La_(w)Ca_(x)Co_(y)O_(3−δ), La_(u)Ca_(w)Fe_(x)Co_(y)O_(3−δ),La_(w)Sr_(x)Co_(y)O_(3−δ), La_(u)Sr_(w)Ti_(x)Fe_(y)O_(3−δ),La_(u)Sr_(w)Co_(x)Fe_(y)O_(3−δ), La_(u)Sr_(w)Ga_(x)Fe_(y)O_(3−δ), or12.8La_(v)Sr_(w)Ga_(x)Fe_(y)O_(3−δ)—Ba_(u)Sr_(v)Fe_(w)Co_(x)Fe_(y)O_(3−δ),wherein u, v, w, x, and y are each in the range of 0-1, and δ varies tomaintain electro-neutrality. In another embodiment, the ITM is aperovskite-type ceramic having a composition of La_(1-x)Sr_(x)CoO_(3−δ)with x in the range of 0.1-0.7. In one embodiment, the ITM is doped witha metallic element selected from the group consisting of Ni, Co, Ti, Zr,and La. In another embodiment, the ITM is doped with a metallic elementselected from the lanthanide group of the periodic table (i.e. metallicchemical elements with atomic numbers 57 through 71). In one embodiment,the ion transport membrane 210 includes at least one coating layerhaving a composition of RBaCO₂O_(5−δ), wherein R is a metallic elementselected from the lanthanide group (i.e. elements with atomic numbers 57through 71) of the periodic table. Preferably R is at least one elementselected from the group consisting of Pr, Nd, Sm, and Gd. In anotherembodiment, the ion transport membrane 210 includes pores in the sizerange of 0.1-10 nm, preferably 0.5-5 nm, more preferably 0.5-3 nm.

In one embodiment, a selectivity of the ion transport membrane 210 withrespect to oxide ions (i.e. O²⁻) is at least 90%, preferably at least92%, more preferably at least 95%, even more preferably at least 99%.Selectivity of an ITM with respect to an ion (e.g. oxide ions) is ameasure of the capability of that ITM to transport the ion (e.g. oxideions). For example, if selectivity of an ITM with respect to oxide ionsis 99%, then 99wt % of permeated substances through the membrane areoxide ions. Selectivity of an ITM with respect to oxide ions may bedetermined by the size of vacancies present in the crystal structure ofthe ITM. Oxide ions form in a reduction reaction when molecular oxygen114 is contacted with an ITM in the feed zone 110 and in the presence offree electrons. An ITM having a 100% selectivity with respect to oxideions only allows the oxide ions to permeate through the membrane. In oneembodiment, a selectivity of the ion transport membrane with respect tocarbon dioxide, elemental nitrogen (i.e. N₂), water vapor, carbonmonoxide, argon, and sulfur is less than 5%, preferably less than 2%,more preferably less than 1%, even more preferably less than 0.5%.

A surface area of the ITM may be in the range of 0.1 m²-50 m²,preferably 0.5-40 m², more preferably 1-30 m², even more preferably10-30 m². In some embodiments, the ion transport membrane 210 has athickness in the range of 0.5-3 mm, preferably 0.5-2 mm, more preferably0.5-1.5 mm, whereas an oxygen flux of the ion transport membrane iswithin the range of 0.5-2.5 μmol·cm⁻²·s⁻¹, preferably 0.5-2μmol·cm⁻²·s⁻¹, more preferably 0.7-1.5 μmol·cm⁻²·s⁻¹ at a temperature inthe range of 800-1,500° C., preferably 800-1,200° C., more preferably800-1,000° C.

In one embodiment, the ITM is supported by a meshed structure 220 thatcovers at least a portion of a side of the ITM that faces the combustionzone. The meshed structure 220 may include rectangular, triangular,hexagonal, and/or spherical meshes having a surface area in the range of10-500 mm², preferably 50-400 mm², more preferably 100-300 mm². Themeshed structure 220 may be made of a high-temperature duty ceramiccomposite that can endure a temperature of up to 1,500° C., preferablyup to 2,000° C., more preferably up to 2,500° C. The meshed structure220, which is a cylindrical structure, may have a compressive strengthof at least 5 MPa, preferably at least 10 MPa, more preferably at least20 MPa, and may be utilized to prevent a collapse of the ITM due to anexcessive compression in the feed zone 110.

In one embodiment, the ITM 210 is secured inside the combustor withbolts and nuts, O-rings (e.g. ceramic or metal rings), and/or gaskets216 to prevent any leakage from outside of the combustion zone 108 toinside of same. Further, the O-rings and/or gaskets 216 may prevent anyleakage from the feed zone 110 to the combustion zone 108 and viceversa.

The combustor 112 further includes a first inlet 212 and a first outlet214 located in the feed zone 110, and a second inlet 208 and a secondoutlet 209 located in the combustion zone 108.

The first inlet 212 is utilized as a passage for loading the feed zone110 with an oxygen-containing stream 136 s. Similarly, the first outlet214 is utilized as a passage for unloading the feed zone 110. In oneembodiment, the first inlet 212 and the first outlet 214 aresubstantially similar, wherein each is a cylindrical port having aninternal diameter in the range of 10-50 mm, preferably 10-40 mm, morepreferably 10-30 mm, and are configured to transfer a pressurized streamhaving a pressure in the range of 1-50 bars, preferably 1-30 bars, morepreferably 1-10 bars.

In one embodiment, the specifications of the second inlet and the secondoutlet are substantially similar to that of the first inlet and thefirst outlet, as described.

The first and the second inlets and the first and second outlets may besecured perpendicular and/or parallel to the longitudinal axis of thecylindrical vessel. For example, in a preferred embodiment, thecylindrical vessel is horizontally oriented and the ITM disposed thereinis horizontally oriented, where the longitudinal axis of the ITM issubstantially parallel to a longitudinal axis of the cylindrical vessel,and the first and the second inlets and first and second outlets areoriented parallel to the longitudinal axis of the cylindrical vessel. Inanother preferred embodiment, the first inlet and the first outlet aredisposed perpendicular to the longitudinal axis of the cylindricalvessel, whereas the second inlet and the second outlet are disposedparallel to said axis.

In one embodiment, the cylindrical vessel is horizontally orientedhaving a first end and a second end, and the first inlet, the firstoutlet, and the second inlet are located on one end (for example thefirst end), while the second outlet is located on the opposite end (forexample the second end), as depicted in FIG. 2A. In another embodiment,the first outlet and the second inlet are located on the same end (forexample the first end), while the first inlet and the second outlet arelocated on the opposite end (for example the second end), as depicted inFIG. 1A, 1B, and 1C. Preferably, in this embodiment, the first outletand the second inlet may be located on the same end (for example thefirst end), while the first inlet and the second outlet may be locatedon the same end (for example the second end). Accordingly, an axial flowof the oxygen-containing stream 136 s in the feed zone 110 iscounter-current relative to an axial flow of the fuel stream 104 s inthe combustion zone 108. In an alternative embodiment, the first inlet212 and the first outlet 214 may be located on a side wall of the vesseland perpendicular to the longitudinal axis of the vessel, while thesecond inlet 208 and the second outlet 209 may preferably be located onopposite ends and parallel to the longitudinal axis of the vessel.

Other than inlets/outlets designed to allow ingress and egress, thevessel may be sealed to prevent any leakage of the oxygen-containingstream 136 s and/or the fuel stream 104 s.

In a preferred embodiment, the combustor 112 further includes a thirdconcentric cylindrical zone which is sandwiched between the first andthe second concentric cylindrical zones, defining a sweep zone 109 (asshown in FIG. 1C). The sweep zone 109 may be configured as a section,wherein molecular oxygen 114 is collected and further be mixed with agaseous stream (e.g. a carbon dioxide stream). Furthermore, the sweepzone 109 may protect the ITM from thermal shocks occurred within thecombustion zone 108, since the ITM is not directly contacted with thecombustion zone 108. According to this embodiment, the combustion zone108 may be made of an impermeable ceramic material that can endure atemperature of up to 1,500° C., preferably up to 2,000° C., morepreferably up to 2,500° C. Accordingly, the sweep zone is defined as thespace between the impermeable ceramic material and the ITM, while thefeed zone is defined by the ITM and an outer wall of the combustor. Inthis case, a recycle stream, which may be an exhaust stream, flows intothe sweep zone and sweep the molecular oxygen, which has been permeatedvia the ITM, away from the sweep zone and into a downstream mixer,wherein the exhaust stream and the molecular oxygen are mixed with afuel to form a combustion mixture to be fed into the combustion zone.Exemplary impermeable ceramic materials may include, but not limited to,borides, carbides, nitrides, and oxides of transition metals selectedfrom the group consisting of Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and Th.For example, hafnium diboride (HfB₂), zirconium diboride (ZrB₂), hafniumnitride (HfN), zirconium nitride (ZrN), titanium carbide (TiC), titaniumnitride (TiN), thorium dioxide (ThO₂), tantalum carbide (TaC), andcomposites thereof.

In one embodiment, the combustor 112, having the third concentriccylindrical zone, further includes a third inlet 222 and a third outlet224 located in the sweep zone. Specification of the third inlet 222 andthe third outlet 224 may preferably be substantially similar to that ofthe first and the second inlets and the first and the second outlets, asdescribed. Furthermore, the third inlet 222 and the third outlet 224 maypreferably be located on the opposite ends and parallel to thelongitudinal axis of the vessel, to create a flow stream in the sweepzone that has a counter-current axial flow relative to an axial flow ofthe fuel stream 104 s in the combustion zone 108 (as depicted in FIG.1C). For example, in a preferred embodiment, the first outlet, thesecond inlet, and the third outlet 224 may be located on the same end(for example the first end), while the first inlet, the second outlet,and the third inlet 222 may be located on the same end (for example thesecond end).

The combustor 112 further includes a swirler 106 that is connected tothe second inlet 208. FIG. 2A shows the combustor 112 in an axialcross-section at a first end, wherein the first and second inlets andthe first outlet are disposed. A fuel stream 104 s enters the combustor112 via a fuel line 104 and is burned within the combustion zone 108 inthe presence of molecular oxygen 114 to form an exhaust stream 118 s.The exhaust stream 118 s may further be utilized to perform work, e.g.by rotating a turbine, or operating an internal combustion engine, etc.In one embodiment, the fuel stream 104 s is introduced into thecombustor 112 via a fuel nozzle, which may be located at the secondinlet 208. The fuel stream 104 s exiting the fuel nozzle, is furtherexpanded (or whirled) by the swirler 106 and is mixed with molecularoxygen 114 that enters the combustion zone 108 via the ITM, which may bemaintained at a temperature in the range of 800-1,500° C., preferably800-1,200° C., more preferably 800-1,000° C. As a result, the fuelstream 104 s is combusted in the combustion zone 108 and forms theexhaust stream 118 s. The fuel stream 104 s may be in a liquid phaseand/or in a gaseous phase before entering the combustion zone 108.

In an alternative embodiment, the fuel stream 104 s enters the combustor112 via a fuel line 104 and is burned within the combustion zone 108 toform an exhaust stream 118 s. The exhaust stream 118 s may further berecycled to the sweep zone 109 to sweep the molecular oxygen 114, whichhas been permeated via the ITM, away from the sweep zone. The exhauststream 118 s, which now includes the molecular oxygen 114, is fed into amixer 134, wherein the molecular oxygen 114 is mixed with the fuelstream 104 s in the presence of the exhaust stream 118 s to form acombustion mixture. The combustion mixture is further delivered to thecombustion zone 108.

The swirler 106 is configured to create a vortex of a fluid (e.g. thefuel stream 104 s) inside the combustion zone 108, which may enhance themixing process and may increase a flux of molecular oxygen 114 via theITM. In the embodiment where the combustion zone is lined with theimpermeable ceramic materials the swirler may improve oxy-combustion byenhancing the mixing process and increasing a residence time of thereactants (i.e. the fuel stream and the molecular oxygen) within thecombustion zone.

The swirler 106 includes adjustable blades 304 with adjustable(variable) angles. Accordingly, the swirler 106 includes a plurality ofblades extending radially from a shaft 302, where each blade has alongitudinal axis and an angle 312 of the longitudinal axis of eachblade 310 is adjustable relative to a longitudinal axis of the shaft 308(as shown in FIG. 3B).

In one embodiment, the adjustable blades 304 are arranged at equallyspaced positions along the circumferential direction of an outerperipheral surface of the shaft 302, and are installed to extend in theaxial direction of the shaft 302. The adjustable blades 304 may beconfigured to swirl a compressed gaseous mixture flowing through thefuel line 104 to form a swirl fluid flow in the combustion zone 108.

The term “adjustable blades”, as used herein, refers to blades that canbe manually or automatically adjusted to a preferred angle (as shown inFIG. 3B). Further, the term “adjustable angle” refers to an angle 312between the longitudinal axis of each blade 310 and the longitudinalaxis of the shaft 308 (as shown in FIG. 3B). In a preferred embodiment,said angle is adjustable within the range of 0 to 85°, preferably 0 to75°, more preferably 30 to 60°. Preferably, said angle may be set to asame value for each blade. Alternatively, each blade may have adifferent angle. In a preferred embodiment, said angle is determinedaccording to the type of the fuel stream 104 s. Preferably, said anglemay instantaneously be adjusted based on variations in the compositionof the fuel stream 104 s during operating the combustor 112. In analternative embodiment, a preferred angle may be set for the bladesbefore the combustor 112 starts, and may not be further adjusted duringoperating the combustor 112. The preferred angle may be determinedaccording to ambient conditions at which the combustor 112 is operating.

Said angle determines a tangential velocity of the fuel stream 104 srelative to the ITM. The tangential velocity, as used here, refers to avelocity measured at any point tangent to an inner surface of the ITM.Accordingly, where the angle is set to zero, a swirl number (i.e. theratio of the axial flux of an angular momentum to the axial flux of anaxial momentum) is less than 0.3, preferably less than 0.2, and thus atangential component of the velocity of the fuel stream is negligible,while an axial component of the velocity is maximized. In contrast, asthe angle increases, the axial component of the velocity of the fuelstream decreases, while a tangential component of the velocityincreases. Accordingly, where the angle is in the range of 45 to 60°,the swirl number rises to a number in the range of 0.65-1, preferably0.7-0.95. Therefore, the swirler 106, which has adjustable blades 304,serves to control an axial velocity (or an axial momentum) of the fuelstream in the combustion zone 108 of the combustor 112 for various fuelstreams. Accordingly, the swirler 106 may be capable of providing a flowstream having a high axial momentum (i.e. a low swirl number in therange of 0-0.5, preferably 0.05-0.2) in the combustion zone 108.Additionally, the swirler 106 may also capable of providing a flowstream having a high angular momentum (i.e. a high swirl number in therange of 0.65-1, preferably 0.7-0.95) in the combustion zone 108. Havinga swirler 106 that creates a flow stream that has a high angularmomentum (i.e. a high swirl number) is advantageous, because the fuelstream may effectively be mixed with the molecular oxygen 114, theoxygen flux of the ITM may be increased, and the residence time of thefuel stream and the molecular oxygen 114 in the combustion zone 108 maybe elevated.

Preferably, the swirler 106 does not rotate around the shaft 302, andthe only movable component of the swirler 106 is the adjustable blades304 that can be adjusted to a preferred angle. However, in anotherembodiment, the swirler 106 rotates around the shaft 302 with arotational speed in the range of 500-5,000 rpm, preferably 1,000-3,000rpm. In view of that, the rotational speed may be determined accordingto the type of the fuel stream 104 s and a flux of the molecular oxygen114. The rotational speed of the swirler 106 may instantaneously beadjusted based on variations in the composition of the fuel stream 104 sduring operating the combustor 112. Alternatively, a constant rotationalspeed may be set for the swirler before the combustor 112 starts, andthe rotational speed may not be further adjusted during operating thecombustor 112. The rotational speed may also be determined according toambient conditions at which the combustor 112 is operating.

Other than the adjustable blades 304 and the shaft 302, the swirler 106may further include a shroud 314 to protect the blades. Furthermore, ina preferred embodiment, the shaft 302 has a hollow space and anactuator, preferably an electric motor or a pneumatic actuator, issecured inside the hollow space to adjust the angle of the blades(preferably automatically).

In another embodiment, the swirler 106 is secured at the second inlet208 such that a longitudinal axis of the shaft 308 is substantiallyparallel to the longitudinal axis of the cylindrical vessel (as shown inFIG. 2A). The swirler 106, however, may be secured at the second inlet208 such that the longitudinal axis of the shaft 308 creates an anglewith the longitudinal axis of the cylindrical vessel, with the anglebeing in the range of 0-45°, preferably 0-30°, to deliver a vortex ofthe fuel stream towards a top and/or a bottom portion of the cylindricalvessel (i.e. towards a top and/or a bottom portion of a side wall of thecylindrical vessel). Preferably, the swirler 106 (or a plurality ofswrilers) may be secured at the second inlet 208 (or a plurality ofinlets) with high-temperature duty O-rings and/or gaskets.

In a preferred embodiment, a length of the adjustable blades are atleast 10%, preferably at least 20% longer than a length of the shroud314 such that they stick out past the shroud and inside the combustionzone to direct the fuel stream further away from the center of thecombustor (or closer to the ITM). In another embodiment, the length ofthe adjustable blades changes around the shaft of the swirler (like aspiral staircase).

According to a second aspect the present disclosure relates to acombustion system 100, including the combustor 112 in accordance withthe first aspect, an oxygen supplier located upstream of and fluidlyconnected to the first inlet 212 via a feed line 136 for supplying anoxygen-containing stream 136 s, and a fuel supplier 102 located upstreamof and fluidly connected to the second inlet 208 via a fuel line 104 forsupplying a fuel stream 104 s.

The oxygen supplier may be an air cylinder or an oxygen cylinder.Preferably, it may also be a primary compressor 138 located upstream ofand fluidly connected to the first inlet 212 via the feed line 136,which delivers an air stream having a temperature in the range of300-600° C., preferably 300-400° C., and a pressure in the range of 1-50bars, preferably 1-30 bars, more preferably 1-10 bars. In addition, aheat exchanger and/or a heater may be adapted to recover heat from theoxygen depleted air.

The oxygen-containing stream 136 s includes oxygen, and may furtherinclude nitrogen and preferably less than 1.0vol %, more preferably lessthan 0.5vol % of argon, carbon dioxide, neon, helium, hydrogen, andwater vapor. Preferably, a pressure of the oxygen-containing stream 136s may be within the range of 1-50 bars, preferably 1-30 bars, morepreferably 1-10 bars, whereas a temperature of the oxygen-containingstream 136 s may be within the range of 600-1,200° C., preferably600-800° C., before entering the combustor 112. Preferably, theoxygen-containing stream 136 s includes less than 1.0 vol %, preferablyless than 0.5 vol %, more preferably less than 0.1 vol %, with volumepercent being relative to the total volume of the oxygen-containingstream 136 s. Furthermore, an oxygen partial pressure of theoxygen-containing stream 136 s may be at least 200 torr, preferably atleast 350 torr, more preferably 500 torr, even more preferably at least600 torr.

The feed line 136 is a tubular channel that is configured to carry theoxygen-containing stream 136 s from the oxygen supplier to the firstinlet 212 of the combustor 112. In a preferred embodiment, the feed line136 is made of a metal or an alloy that is coated with a polymer (e.g.epoxy), and is configured to bear a pressure up to 100 bars, preferablyup to 200 bars, even more preferably up to 500 bars. In anotherembodiment, the feed line is made of a polymer (e.g. polyvinylchloride,polyethylene, polypropylene, polytetrafluoroethylene, etc.), and isconfigured to bear a pressure up to 50 bars, preferably up to 100 bars,even more preferably up to 200 bars.

The fuel supplier 102 may be a methane cylinder or an effluent of achemical plant that provides a methane stream. Furthermore, the fuelsupplier 102 may be a petrochemical plant that provides an ethanestream. However, in a preferred embodiment, the fuel supplier 102 is agasification plant that provides a syngas stream. Preferably, the fuelsupplier 102 is a methane reforming plant that provides a syngas stream.More preferably, the fuel supplier 102 is a solar methane reformingplant that provides a syngas stream. Accordingly, the fuel stream 104 smay be a methane stream, an ethane stream, a hydrogen stream, orpreferably a syngas stream. Besides, the fuel stream 104 s may also be ahydrocarbon stream (in liquid phase and/or in gaseous phase) that can becombusted, e.g. a stream including hydrocarbon compounds (alkanes,alkenes, alkynes, cycloalkanes, etc.) having a carbon content in therange of C₁-C₂₀, preferably C₁-C₁₂, more preferably C₁-C₈. In somepreferred embodiments, the fuel stream includes less than 1000 ppm,preferably less than 500 ppm, more preferably less than 100 ppm ofnitrogen. Further, the fuel stream includes less than 500 ppm,preferably less than 100 ppm, more preferably less than 50 ppm ofsulfur. Having a fuel stream with a reduced sulfur content may beadvantageous towards preventing formation of sulfur oxides (SO_(x)) inthe combustion zone 108, while a fuel stream with a reduced nitrogencontent may be advantageous towards preventing formation of nitrogenoxides (NO_(x)) in the combustion zone 108. Preferably, a pressure ofthe fuel stream may be within the range of 1-50 bars, preferably 1-30bars, more preferably 1-10 bars, whereas a temperature of the fuelstream may be within the range of 600-1,200° C., preferably 600-1,000°C.

In some alternative embodiments, the fuel supplier 102 may also refer toa series of operational units that provides a fuel stream 104 s having apredetermined pressure, a predetermined temperature, a predeterminedflow rate, and a predetermined water content. For example, the fuelsupplier may include a dehydrator and/or a dehumidifier, whereby a watercontent of the fuel stream 104 s is reduced to less than 1.0 vol %,preferably less than 0.5 vol %, more preferably less than 0.1 vol %,with volume percent being relative to the total volume of the fuelstream. In addition, the fuel supplier may include a sulfur separator toreduce a sulfur content of the fuel stream to said sulfur contentranges, as described. Preferably, the fuel supplier may also include aseparating unit (or a series of separating units) that separatesnon-oxygen substances such as carbon dioxide, water vapor, andpreferably nitrogen from the fuel stream to said sulfur content ranges,as described. A pressure and a flow rate of the fuel stream may beadjusted via an auxiliary compressor in the fuel supplier to be withinthe range of 1-50 bars, preferably 1-30 bars, more preferably 1-10 bars.In addition, a temperature of the fuel stream 104 s may be adjusted by aheater, a cooler, and/or a heat exchanger, which is present in the fuelsupplier, to be within the range of 600-1,200° C., preferably 600-1,000°C.

In a preferred embodiment, the fuel stream 104 s is a syngas streamhaving hydrogen and carbon monoxide, and one or more of carbon dioxide,methane, and ethane. The syngas stream may further include traces amount(preferably less than 0.1 vol %) of nitrogen, water vapor, sulfur,hydrogen sulfide, argon, helium, nitrogen oxides (i.e. nitric oxide,nitrous oxide, nitrogen dioxide), or sulfur dioxide.

In a preferred embodiment, the fuel line 104 is made of a metal or analloy that is coated with a polymer (e.g. epoxy), and is configured tobear a pressure up to 100 bars, preferably up to 200 bars, even morepreferably up to 500 bars. In another embodiment, the fuel line is madeof a polymer (e.g. polyvinylchloride, polyethylene, polypropylene,polytetrafluoroethylene, etc.), and is configured to bear a pressure upto 50 bars, preferably up to 100 bars, even more preferably up to 200bars.

In one embodiment, the combustion system 100 further includes anexpander 116 located downstream of and fluidly connected to the secondoutlet 209 via an exhaust line 118 for expanding an exhaust stream 118 sto generate power.

In one embodiment, the term “expander” may refer to a centrifugal or anaxial flow turbine, wherein a pressurized stream (i.e. the exhauststream) is expanded in an isentropic process (i.e. a constant entropyprocess) to produce shaft work when the pressurized stream passesthrough vanes of said turbine. The shaft work may be utilized to drive acompressor, a generator (for generating electricity), a crankshaft of anengine, etc. In an alternative embodiment, the expander 116 may refer toan internal combustion engine, which is fluidly connected to acombustion chamber, wherein a pressurized stream (i.e. the exhauststream) is accumulated. Accordingly, the pressurized stream may beutilized to produce shaft work in a two-stroke cycle (i.e. a powergenerating method with two strokes (up and down movements) of a pistonduring only one crankshaft revolution).

The exhaust stream 118 s includes carbon dioxide and water vapor, andmay also include less than 1.0 vol %, preferably less than 0.5 vol % ofcarbon monoxide, nitrogen oxides (i.e. nitric oxide, nitrous oxide,nitrogen dioxide), sulfur dioxide, argon, helium, and/or carbonic acid.In addition, a temperature of the exhaust stream 118 s prior toexpanding in the expander 116, is preferably within the range of800-2,000° C., preferably 800-1,500° C., more preferably 800-1,200° C.,whereas the exhaust stream 118 s after expanding may have a temperaturein the range of 100-1,000° C., preferably 100-500° C., more preferably150-500° C. The exhaust stream 118 s may turn into a double phase stream(i.e. containing both a gaseous phase and a liquid phase), althoughpreferably the exhaust stream 118 s is in the gaseous phase.

The exhaust stream 118 s may further be utilized to heat up a processstream in the combustion system. Furthermore, the exhaust stream 118 smay be utilized to heat up a process stream in a power plant, a chemicalprocessing plant, or a refining plant. Additionally, the exhaust stream118 s may be used for operating pneumatic actuators and/or pneumaticsystems in a power plant, a chemical processing plant, or a refiningplant.

The exhaust line 118 is made of a high-temperature duty metal or analloy, and is configured to bear a pressure up to 50 bars, preferably upto 100 bars, even more preferably up to 200 bars, while also configuredto endure a temperature up to 1,500° C., preferably 2,000° C., morepreferably 2,500° C.

In one embodiment, the combustion system 100 further includes a swirlercontrol unit. The swirler control unit refers to a closed-loop controlsystem, which is adapted to adjust an angle of the blades of the swirlerbased on the composition of the fuel stream 104 s and/or the compositionof the exhaust stream 118 s. Accordingly, the swirler control unit mayinclude a first gas analyzer 156 disposed on the fuel line 104, which isconfigured to determine the composition of the fuel stream 104 s. Theswirler control unit may further include a second gas analyzer 152disposed on the exhaust line 118 that is configured to determine thecomposition of the exhaust stream 118 s.

In one embodiment, the first and the second gas analyzers aresubstantially similar; each may be a gas chromatographer (GC) that maybe couple to a mass spectrometer (MS). Furthermore, said gas analyzersmay be IR-operated analyzers (i.e. IR gas analyzers), although the typeof gas analyzers is not meant to be limiting and various other type ofgas composition measurement instrument may be used.

The swirler control unit may further include an actuator connected tothe blades of the swirler 106. The actuator is configured to adjust anangle of the blades. As described previously, the actuator maypreferably be an electric motor or a pneumatic actuator. For example, insome embodiments, the shaft 302 of the swirler 106 has a hollow space,wherein an electric motor, which has a shaft, is located. Further, eachblade has a shaft 306, which is perpendicular to the longitudinal axisof the blade. Accordingly, the shaft of the electric motor is coupled tothe shaft of each of the blades, preferably via a gear box. Therefore,the electric motor is adapted to determine the angle of the blades ofthe swirler 106. Alternatively, in a preferred embodiment, the actuatoris pneumatically operated. The actuator may also be hydraulicallyoperated.

The swirler control unit may further include a processor 150 that isconfigured to receive a first signal 158 from the first gas analyzer 156and a second signal 154 from the second gas analyzer 152, and totransmit a first output signal 159 to the actuator. The processor 150may refer to a programmable hardware device that is adapted to calculatea predetermined angle (as the first output signal 159) based upon thefirst and the second signals that contain the composition of the fueland the exhaust streams, respectively. The first and the second signalsmay further include the temperature, the pressure, and the flow rate ofthe fuel and the exhaust streams.

In a preferred embodiment, the predetermined angle is adjustable withinthe range of 0 to 85°, preferably 0 to 75°, more preferably 30 to 60°,and is instantaneously adjusted based on variations in the compositionof the fuel and the exhaust streams during operating the combustor 112.In one embodiment, the fuel stream is a syngas stream, which is producedvia a solar methane reforming process, and the predetermined angle iscalculated based on the following formula:

SA=a*F+b*C+c*H+d

wherein SA is the predetermined angle, F is a combustion firing rate(i.e. the energy release rate in the combustor 112), C is a percentageof carbon dioxide in the fuel stream, and H is the percentage ofhydrogen in the fuel stream. In addition, each of a, b, c, and d isnumerical values in the range of −1000 to 1000, preferably −500 to 500.

In one embodiment, the predetermined angle of the adjustable blades isset relative to a carbon dioxide content (i.e. a partial pressure ofcarbon dioxide) of the fuel stream (or the combustion mixture). Forexample, if the carbon dioxide content is above 30 vol %, preferablyabove 50 vol %, the predetermined angle is wider, and vice versa.However, in a preferred embodiment, the predetermined angle of theadjustable blades is set based on an amount of hydrocarbon compoundspresent in the fuel stream and/or an amount of carbon dioxide in theexhaust stream.

In one embodiment, the combustion system 100 further includes a flowcontrol unit, which is a closed-loop control system adapted to controlthe volumetric flow rate of the oxygen-containing stream 136 s based onthe composition and the volumetric flow rate of the fuel stream 104 s.

In a preferred embodiment, the flow control unit includes the first gasanalyzer 156 of the swirler control unit, which is utilized to determinethe composition of the fuel stream 104 s, and to generate a thirdsignal, which is substantially similar to the first signal 158. Inanother embodiment, the flow control unit includes a third gas analyzer,which is substantially similar to the first gas analyzer 156, disposedon the fuel line 104 configured to determine the composition of the fuelstream 104 s.

The flow control unit may further include a flowmeter 144 disposed onthe fuel line 104 configured to determine the volumetric flow rate ofthe fuel stream 104 s, and to generate a flow rate signal 162.

The flow control unit may further include a first control valve 140disposed on the feed line 136 configured to control a volumetric flowrate of the oxygen-containing stream 136 s. The first control valve 140may be a check valve, a ball valve, a gate valve, or a diaphragm valves,although the valve type is not meant to be limiting and various othertype of valves may also be used.

The flow control unit may further include a flow controller 160 that isconfigured to receive the third signal from the first gas analyzer 156(or the third gas analyzer) and the flow rate signal 162 from theflowmeter 144, and to generate and transmit a second output signal 164to the first control valve 140. The flow controller 160 may refer to aprogrammable hardware device that is adapted to measure a predeterminedvolumetric flow rate (as the second output signal 164) based upon theflow rate signal 162 and the third signal.

In one embodiment, the flow control unit adjusts the volumetric flowrate of the oxygen-containing stream 136 s to be within the range of1-5,000 L/min, preferably 100-3,000 L/min, more preferably 500-2,000L/min per 1.0 m² surface area of the ion transport membrane 210.

In an alternative embodiment, the flow control unit adjusts a volumetricflow rate ratio of the fuel stream 104 s to the oxygen-containing stream136 s to be within the range of 0.9-1.1, preferably about 1. Forexample, in circumstances where the volumetric flow rate of the fuelstream 104 s reduces, the volumetric flow rate of the oxygen-containingstream 136 s also reduces to maintain the volumetric flow ratio to bewithin the range of 0.9-1.1, preferably about 1. Likewise, in some othercircumstances where the composition of the fuel stream 104 s changes,the volumetric flow rate of the oxygen-containing stream 136 s is alsochanged to maintain the volumetric flow ratio to be within the range of0.9-1.1, preferably about 1.

In some embodiments, the combustion system 100 further includes arecycle line 126 that fluidly connects the exhaust line 118 to the fuelline 104. Preferably, the recycle line 126 is substantially similar tothe exhaust line 118. Accordingly, the combustion system furtherincludes a temperature control unit, which is a closed-loop controlsystem adapted to control the temperature of the fuel stream 104 s basedon the temperature of the exhaust stream 118 s.

The temperature control unit may include a temperature sensor 172disposed on the exhaust line 118 that is configured to determine atemperature of the exhaust stream 118 s, and to generate a temperaturesignal 174. The temperature sensor 172 may preferably be a thermocouple,although the sensor type is not meant to be limiting and various othertype of temperature sensors may also be used. Further, the temperaturecontrol unit may include a second control valve 128, which may besubstantially similar to the first control valve 140, disposed on therecycle line 126 configured to control the volumetric flow rate of theexhaust stream 118 s.

Furthermore, the temperature control unit may include a temperaturecontroller 170 that is configured to receive the temperature signal 174,and to transmit a third output signal 176 to the second control valve128. The temperature controller 170 may refer to a programmable hardwaredevice that is adapted to measure a predetermined temperature (as thethird output signal 176) based upon the temperature signal 174.

Since the temperature control unit utilizes a thermal energy of theexhaust stream 118 s to control the temperature of the fuel stream 104s, a heat exchanger and/or a heater may be disposed on the recycle line126 to raise the temperature of the exhaust stream 118 s, in cases wherethe temperature of the exhaust stream 118 s is lower than 500° C.,preferably lower than 800° C.

In one embodiment, the combustion system 100 further includes a mixer134 located upstream of the combustor 112 and is fluidly connected tothe fuel line 104 and the recycle line 126. In a preferred embodiment,the mixer 134 is configured to mix the fuel stream 104 s with theexhaust stream 118 s.

The mixer 134 may refer to an operational unit adapted to mix aplurality of gas streams, preferably at low-to-medium pressures (i.e. upto 50 bars, preferably up to 20 bars), and deliver a combustion mixturehaving a predetermined pressure (e.g. within the range of 1-50 bars,preferably 1-30 bars, more preferably 1-10 bars), and a predeterminedtemperature (e.g. within the range of 200-500° C., preferably 200-400°C.).

In a preferred embodiment, the combustion system 100 further includes anoxygen-depleted line 142 that is fluidly connected to the first outlet214, and a primary heat exchanger 132 disposed on the recycle line 126and upstream of the mixer 134, while the primary heat exchanger 132 islocated on the oxygen-depleted line 142 and downstream of the firstoutlet 214. Accordingly, the primary heat exchanger 132 is configured toheat exchange the exhaust stream 118 s with an oxygen-depleted stream142 s that egresses the first outlet 214 to raise the temperature of theexhaust stream 118 s, in cases where the temperature of the exhauststream 118 s is lower than 500° C., preferably lower than 800° C.

In another embodiment, the combustion system 100 further includes asecondary heat exchanger 133 disposed on the feed line 136 and upstreamof the first inlet 212, while the secondary heat exchanger 133 islocated on the oxygen-depleted line 142 and downstream of the firstoutlet 214. Accordingly, the secondary heat exchanger 133 is configuredto heat exchange the oxygen-containing stream 136 s with anoxygen-depleted stream 142 s that egresses the first outlet 214. Theprimary and the secondary heat exchangers may preferably be shell andtube heat exchangers, although the heat exchanger type is not meant tobe limiting and various other heat exchangers may also be used.

In an alternative embodiment, the oxygen-depleted line 142 is fluidlyconnected to a gas turbine, wherein the oxygen-depleted stream 142 spasses through vanes of the gas turbine to generate shaft work.

In a preferred embodiment, the combustion system 100 further includes acondenser 120 located downstream of and fluidly connected to theexpander 116 via the exhaust line 118. Preferably, the condenser 120 isconfigured to separate a liquid phase from the exhaust stream 118 s. Thecondenser 120 may be a heat exchanger, a cooling system, or arefrigeration system, although the condenser type is not meant to belimiting and various other condensers may also be used.

In one embodiment, the combustor 112 of the combustion system 100includes the sweep zone 109 which is sandwiched between the feed zone110 and the combustion zone 108, and the recycle line 126 fluidlyconnects the exhaust line 118 to the third inlet 222. Accordingly, theexhaust stream 118 s flows into the sweep zone 109, which may sweep themolecular oxygen 114 away from the sweep zone 109 and further egressesthe third outlet 224. The exhaust stream 118 s that now includes themolecular oxygen 114 enters the mixer 134 and is mixed with the fuelstream 104 s to form the combustion mixture, which is further fed intothe combustion zone 108.

According to a third aspect the present disclosure relates to a processfor combusting the fuel stream 104 s (as described previously),involving delivering the oxygen-containing stream 136 s (as describedpreviously) to the first inlet 212 of a combustor 112 having a feed zone110 and a combustion zone. Accordingly, molecular oxygen 114 present inthe oxygen-containing stream 136 s is transported to the combustion zonethrough the ion transport membrane 210. The oxygen-containing stream 136s may be delivered via the primary compressor 138, which is locatedupstream of the first inlet 212.

The process further involves delivering the fuel stream 104 s to thesecond inlet 208 of the combustor 112. According to the presentdisclosure, in order to enhance mixing the fuel stream 104 s with themolecular oxygen 114 and to increase a residence time of the fuel stream104 s and the molecular oxygen 114 in the combustion zone, the fuelstream 104 s is expanded and/or agitated via the swirler 106, which isdisposed at the second inlet 208. Further, the fuel stream 104 s iscombusted in the presence of the molecular oxygen 114 via anoxy-combustion, and forms the exhaust stream 118 s. As discussed, theexhaust stream 118 s includes water vapor and carbon dioxide, and mayalso include less than 1.0 vol %, preferably less than 0.5 vol % ofcarbon monoxide, nitrogen oxides (i.e. nitric oxide, nitrous oxide,nitrogen dioxide), sulfur dioxide, argon, helium, and/or carbonic acid.The exhaust stream 118 s, which egresses the second outlet 209, mayfurther be expanded in the expander 116 (as described previously) togenerate power.

In a preferred embodiment, the process further involves mixing a portionof the exhaust stream 118 s with the fuel stream 104 s via the mixer 134prior to delivering the fuel stream 104 s to the second inlet 208 of thecombustor 112. Although, the exhaust stream 118 s to be mixed with thefuel stream 104 s includes water vapor, the process may preferablyinvolve cooling the exhaust stream 118 s to form a water stream 124 sand a carbon dioxide stream 122 s, and further mixing the carbon dioxidestream 122 s with the fuel stream 104 s. Furthermore, the process mayinvolve heat exchanging the carbon dioxide stream 122 s with theoxygen-depleted stream 142 s, which egresses the first outlet 214 of thecombustor 112, to adjust the temperature of the exhaust stream 118 sprior to mixing the same with the fuel stream 104 s.

In another preferred embodiment, the process further involves heatexchanging the oxygen-containing stream 136 s with the oxygen-depletedstream 142 s, prior to delivering the oxygen-containing stream 136 s tothe first inlet 212 of the combustor 112. Heat exchanging theoxygen-containing stream 136 s with the oxygen-depleted stream 142 s mayeliminate the need for an additional process step to adjust thetemperature of the oxygen-containing stream 136 s prior to deliveringthe same to the combustor 112.

The process further involves adjusting an angle of each blade of theswirler 106 based on the composition of the fuel stream 104 s and/or thecomposition of the exhaust stream 118 s via the swirler control unit.Preferably, the angle of each blade is adjusted instantaneously based onthe variations in the composition of the fuel stream 104 s and/or thecomposition of the exhaust stream 118 s.

In one embodiment, the process further involves controlling thevolumetric flow rate of the oxygen-containing stream 136 s based on thecomposition and the volumetric flow rate of the fuel stream 104 s viathe flow control unit.

In one embodiment, the process further involves controlling thetemperature of the fuel stream 104 s based on the temperature of theexhaust stream 118 s via the temperature control unit.

In one embodiment, the process further involves cooling the exhauststream 118 s via the condenser 120 to form a liquid phase includingwater and a gaseous phase including carbon dioxide. The exhaust stream118 s may be cooled to room temperature (i.e. 25° C.), preferably atemperature below room temperature and above water freezing point (e.g.15° C.), at atmospheric pressure. Other than water, the liquid phase mayalso include less than 1.0vol %, preferably less than 0.5 vol % carbonicacid. The gaseous phase, however, includes carbon dioxide and no morethan 0.5 vol %, preferably no more than 0.1 vol % of nitrogen, hydrogen,carbon monoxide, argon, helium, methane, and/or ethane.

In one embodiment, the method of combusting the fuel stream 104 sfurther involves separating the liquid phase from the gaseous phase, forexample via a vapor-liquid separator. In a preferred embodiment, thegaseous phase is nearly a pure carbon dioxide having at least 99 vol %,preferably at least 99.5 vol %, more preferably at least 99.9 vol %carbon dioxide, and thus the method further involves injecting thegaseous phase into a geological formation. The gaseous phase may also beused in supercritical extraction systems or in processes where alow/medium/high pressure carbon dioxide stream is needed.

According to a fourth aspect the present disclosure relates to a processfor combusting the fuel stream, involving combusting the fuel streamwith molecular oxygen 114 in the combustion zone of a combustor having afeed zone, a combustion zone, and a sweep zone.

The process in accordance with the fourth aspect further involvesdelivering the oxygen-containing stream 136 s to the first inlet 212 ofthe combustor, wherein molecular oxygen 114 present in theoxygen-containing stream 136 s is transported to the sweep zone 109through the ion transport membrane 210.

The process further involves flowing a portion of the exhaust stream 118s, which may initially be formed by combusting the fuel stream in thepresence of molecular oxygen 114 in the combustion zone, into the thirdinlet 222 of the combustor to sweep the molecular oxygen 114 away fromthe sweep zone 109 and to form an oxygen-enriched stream. The exhauststream 118 s may be flowed into the sweep zone 109 via a secondarycompressor 130, which is located upstream of the third inlet 222 andfluidly connected to the recycle line 126. In one embodiment, theoxygen-enriched stream includes oxygen, carbon dioxide, and water vapor,and may also include less than 1.0vol %, preferably less than 0.5 vol %of carbon monoxide, nitrogen, hydrogen, argon, and helium. Preferably,the exhaust stream 118 s is first separated to the water stream 124 sand the carbon dioxide stream 122 s, and the carbon dioxide stream flowsinto the sweep zone 109. Accordingly, the oxygen-enriched streamincludes oxygen and carbon dioxide, and may also include less than 2.0vol %, preferably less than 1.0 vol % of water vapor, carbon monoxide,nitrogen, hydrogen, argon, and helium.

The process further involves mixing the oxygen-enriched stream with thefuel stream in the mixer 134 (as described previously) to form acombustion mixture that includes methane, ethane, hydrogen, carbonmonoxide, water vapor, carbon dioxide, and/or hydrocarbon compounds suchas alkanes, alkenes, alkynes, cycloalkanes, etc. preferably having acarbon content in the range of C₁-C₂₀, preferably C₁-C₁₂, morepreferably C₁-C₈. Preferably, a volume fraction of water vapor in thecombustion mixture is less than 0.005, more preferably less than 0.001.

The process further involves delivering the combustion mixture to thesecond inlet 208 of the combustor, wherein the combustion mixture iswhirled (i.e. expanded and/or agitated) in the combustion zone via theswirler and is combusted to form the exhaust stream 118 s.

The process further involves repeating flowing the exhaust stream 118 sinto the third inlet 222 of the combustor, mixing the oxygen-enrichedstream with the fuel stream in the mixer 134, and delivering thecombustion mixture to the second inlet 208 of the combustor to combust.

In a preferred embodiment, the process further involves adjusting anangle of each blade of the swirler based on the composition of thecombustion mixture. Preferably, the angle of each blade is adjustedinstantaneously based on the variations in the composition of thecombustion mixture.

The examples below are intended to further illustrate protocols for thecombustor, the combustion system, and the process for combusting thefuel stream with the combustion system, and are not intended to limitthe scope of the claims.

EXAMPLE 1

The below examples relate to an ion transport membrane (ITM) integratedto a fuel flexible combustor in a gas turbine system, which referred toas an ITM integrated combustor. Further, a feedback control system isadapted to ensure efficient combustion under a syngas stream, which isproduced via a solar reforming process, having a variable composition.

The examples further relate to an ITM integrated system that includes ahydrocarbon solar reforming system or other sources of producing asyngas stream, the ITM integrated combustor, wherein the syngas streamtakes place either in premixed or non-premixed condition, a variableswirler and a control assembly to change the angle of the vanes of theswirler, wherein the vane angle changes between zero and 75°, dependingon the prevailing conditions including the fuel composition, exhaust gastemperature and composition of the exhaust, an second feedback controlsystem that includes various gas composition sensors, gas flow metersensors and gas state sensors that individually or collectivelycommunicate to the swirler control unit, recycled gas control unit andair flow control unit, and other auxiliary accessories that ensureproper flow communication in the system.

EXAMPLE 2

A reformed syngas fuel was delivered to the ITM integrated combustor.The gas detector and the gas flowmeter 144 provided a feedback signal,which contain information about the composition and volume of syngasfuel being delivered to the swirler, to the air control unit. Next, theair control unit determined the appropriate quantity of air to besupplied and communicated same to the air mass controller.

On the other hand, the gas detector disposed at the exterior of thecombustor communicated the composition of the combustion product to theswirler control unit. Then, the swirler control unit determined theappropriate blade angle for that particular fuel composition. Having theadjustable swirler at the inlet of the ITM combustor is advantageousbecause, it enhance the permeation of the oxygen due to a quick pick upof oxygen by the swirling flow adjacent to the ITM. Further, it improvesthe mixing of the fuel (i.e. the syngas stream) and molecular oxygen formore efficient combustion in the ITM combustor. Additionally, theswirler increases the residence time of the reactants for completecombustion of the fuel.

A plurality of sensors, which are installed at the exit of thecombustor, further communicated the temperature and the pressure of theexhaust, which is CO₂/H₂O or preferably CO₂, to a recycle gas controlunit to adjust the flow rate of the recycle stream as well as thetemperature of the influent of the combustor to prevent damage to thecombustor and the turbine. These sensor signals also communicated withthe swirler control unit. The feedback from the control units was usedto simultaneously control the air flow rates, the swirler blade anglesand the amount of exhaust gas recycled to achieve a stable combustionand gas emission free combustion products.

The ITM combustor further included a sweep zone, which was separatedfrom the combustion zone of the combustor, and molecular oxygen waspermeated into the sweep zone via the ITM. The temperature of thepermeated oxygen was raised because it was in direct contact with thewall of the combustion zone, while the sweep zone protects the ITM fromthermal shock and failure. The oxygen-depleted air at high temperaturewas also used to preheat the compressed air leading to partial heatrecovery.

In some circumstances where water droplets were observed in the exhauststream, the exhaust stream was first cooled and a liquid phase wasseparated, and the gaseous phase, which only includes CO₂ was recycled.

EXAMPLE 3

The adjustable swirler, which has been used in the combustor, is shownin FIG. 3A, 3B, and 3C. It consists of a shaft, a plurality of blades,and an outer casing (i.e. a shroud). The actuator, which rotates theblades, was secured inside the shaft.

To achieve a preferable control over the swirler control unit, a datasetcontaining a preferred swirl angle at each operating condition has beenstored in the memory (CPU) of the control system. This dataset had beenobtained via a series of trial and error experiments to obtain thepreferred swirl angle that provides the most stabilized combustion atvarious fuel compositions. The details of the experimental analysis aregiven in the below examples.

EXAMPLE 4

We designed and carried out a series of experiments as a case study togenerate sample data for a preferred condition of an ITM-swirlercombustor. Three swirler angles 30°, 45°, and 55° with swirl numbers ofapproximately 0.38, 1.67, and 0.95, respectively were tested. Methane(CH₄) and methane (CH₄)/hydrogen (H₂) fuel mixtures were used ascharacteristic syngas fuels. Experiments were conducted by varying thecarbon dioxide (CO₂) in the oxygen (O₂)/carbon dioxide (CO₂) oxidizermixture to determine the combustor stability of CH₄ and CH₄/H₂ fuelswhen the swirler at different angles were used. CO₂ was added tomoderate the temperature of the flame to an acceptable limit to preventdamage to the combustor and to the gas turbine blades, while alsoserving as an energy carrier. The amount of CO₂ that extinguished theflame was used as the surrogate to describe the combustor stability.Therefore, the combustion operating conditions (i.e. at a specified fuelstream and a specified swirler angle, etc.) that could withstand ahigher amount of CO₂ before being extinguished were assumed more stable.

EXAMPLE 5

Data of the stability limit at different operating conditions aresummarized in Table 1. In addition, FIG. 4A, 4B, and 4C show thestability limit of a CH₄ and a CH₄/H₂ fuel at different swirl angles.According to this figure, the firing rate (combustor load) significantlyaffected the stability of the combustor due to the combined effect ofthe amount of the heat released in the combustor, the combustion productresidence time, and the effective mixing of air with oxidizer. Resultsfurther show that the addition of hydrogen extends the stability ofmethane flame due to hydrogen higher extinction strain rate resistanceas compared to the case of pure methane. This implies that by outrightchange of fuel or fuel compositions, the stability of the combustion arehighly affected. For instance, by increasing the H₂ composition from 0%to 20% in CH₄/H₂ flame, the flame was able to withstand an addition ofabout 3%, 3% and 5% of CO₂ for a swirler blade angle of 30, 45, and 55degrees, respectively before the flame extinguishes.

TABLE 1 Blow off point at different operating conditions. Blow offHydrogen Concentration Firing rate (percentage of CO₂ in Swirler (%)(MW/m3) O₂/CO₂ oxidizer) 30 0 4.5 77.1 4 77.2 3.5 78.7 3 80.7 20 4.580.2 4 80.1 3.5 80.9 3 82.2 45 0 4.5 74.8 4 76.6 3.5 78.2 3 80.7 20 4.578.2 4 79.6 3.5 80.7 3 81.8 55 0 4.5 82.5 4 83.5 3.5 86 3 87.5 20 4.587.5 4 88.3 3.5 88.9 3 89.5

EXAMPLE 6

Another point of interest is how the swirler impacts the flamestability. The presence of the swirler was shown to enhance thefuel-oxidizer mixing for an efficient combustion. The results show thatin a non-swirling flow, long jet like flame with narrow stability rangewas observed. The flame, however, becomes compact with a v-shapeconfiguration under swirling flow conditions. In FIG. 5A and 5B, thedependency of the flame stability on the swirl number for both fuelstreams CH₄ and CH₄/H₂ are shown. There is a marginal difference on theeffect of increasing swirl angle from 30° to 45°, for both fuel streamsCH₄ and CH₄/H₂. However, an increase in the swirl number from 45° to 55°resulted in an increase in the amount CO₂. The flame could withstandbefore the flame extinguishes by about 8% for 0% H₂ and 10% for 20% H₂.

EXAMPLE 7

The multi-component factors of oxidizer mixture, fuel type and mixtures,firing rate and swirl number was shown to have varying effects on theemissions, flame stability and temperature distribution within thecombustor. Accordingly, we obtained a multi-regression equation thatpredict the minimum swirl angle for a stable combustion in term of thefiring rate, percentage of CO₂ in the oxidizer mixture and the H₂ in theCH₄/H₂ mixture as given in Eq. (1):

SW=7.3594F+3.4071C−0.5196H−263.29   (1)

where SW is the minimum swirl angle to ensure continuous stableoperation of the combustor, F is the combustion firing rate in MW/m³ ofthe combustor volume, C is the CO₂ percentage in the O₂/CO₂ oxidizermixture, and H is the H₂ percentage in the CH₄/H₂ fuel mixture.

EXAMPLE 8

Different operating conditions were combined to obtain stability limitsfor combustion with the swirler blade angles in the range of 30° to 55°.These operating conditions were substituted in the obtained equation(Eq. (1)). The experimental results and those obtained using Eq. 1 arepresented in Table 2, and also illustrated in FIG. 6. It is important tonote that each data point only shows the minimum swirl angle at which acombination of factors (fuel composition, oxidizer composition, firingrate) could achieve the flame stability. A good prediction of theminimum swirl angle for a stable combustion was observed (as shown inFIG. 6).

TABLE 2 Comparison of the experimental and predicted minimum swirl anglefor combustor stability. Operating conditions Blow off Hydrogen(percentage of Prediction Firing rate Concentration CO₂ in O₂/CO₂Minimum swirl angle error Data set (MW/m3) (%) oxidizer) ExperimentalNumerical (%) 1 4.5 0 77.1 30 32.51703 8.39 2 4 0 77.2 30 29.17804 2.743 3.5 0 78.7 30 30.60905 2.03 4 3 0 80.7 30 33.74364 12.48 5 4.5 0 82.555 50.9156 7.43 6 4 0 83.5 55 50.64304 7.92 7 3.5 0 86 55 55.4812 0.87 83 0 87.5 55 56.91221 3.48 9 4.5 20 80.2 30 32.68737 8.96 10 4 20 80.1 3028.66695 4.44 11 3.5 20 80.9 30 27.71297 7.62 12 3 20 82.2 30 28.462555.12 13 4.5 20 87.5 55 57.55951 4.65 14 4 20 88.3 55 56.60553 2.92 153.5 20 88.9 55 54.97011 0.05 16 3 20 89.5 55 53.3347 3.03

EXAMPLE 9

In industrial settings, where in-situ control is demanded, an electroniccontrol unit (ECU) can be preloaded with a large amount of data or theECU can be connected to a data banks. In such cases, the combustor loadrequirement (firing rate), the amount of CO₂ needed (to achieve thepreferable turbulence and temperature limit of the combustor), the typeof fuel supplied, and other constrains can be mapped against the minimumswirl angle in the data bank, preloaded data, and/or an equationprogrammed within the ECU. The ECU will communicate same to the swirlercontroller to maintain a continuous stable operation for the combustor.

1. A combustor, comprising: a cylindrical vessel with an internal cavity; an ion transport membrane that divides the internal cavity of said vessel into a first and a second concentric cylindrical zone, wherein the first concentric cylindrical zone is a feed zone and the second concentric cylindrical zone is a combustion zone; a first inlet and a first outlet located in the feed zone, and a second inlet and a second outlet located in the combustion zone; and a swirler that is connected to the second inlet, wherein the swirler has adjustable blades with adjustable angles.
 2. The combustor of claim 1, wherein the swirler comprises a plurality of blades extending radially from a shaft, wherein each blade has a longitudinal axis and an angle of the longitudinal axis of each blade is adjustable relative to a longitudinal axis of the shaft.
 3. The combustor of claim 2, wherein the angle of the longitudinal axis of each blade is adjustable in the range of 0 to 85 degrees relative to the longitudinal axis of the shaft.
 4. The combustor of claim 1, further comprising: a third concentric cylindrical zone which is sandwiched between the first and the second concentric cylindrical zones, defining a sweep zone; and a third inlet and a third outlet located in the sweep zone.
 5. A combustion system, comprising: the combustor of claim 1; an oxygen supplier located upstream of and fluidly connected to the first inlet via a feed line for supplying an oxygen-containing stream; and a fuel supplier located upstream of and fluidly connected to the second inlet via a fuel line for supplying a fuel stream.
 6. The combustion system of claim 5, further comprising: an expander located downstream of and fluidly connected to the second outlet via an exhaust line for expanding an exhaust stream to generate power.
 7. The combustion system of claim 6, further comprising: a swirler control unit comprising a first gas analyzer disposed on the fuel line configured to determine a composition of the fuel stream, a second gas analyzer disposed on the exhaust line configured to determine a composition of the exhaust stream, an actuator connected to the adjustable blades of the swirler configured to adjust an angle of the adjustable blades, and a processor that is configured to receive a first signal from the first gas analyzer and a second signal from the second gas analyzer, and to transmit a first output signal to the actuator, wherein the swirler control unit is configured to adjust an angle of the adjustable blades based on the composition of the fuel stream and the exhaust stream.
 8. The combustion system of claim 6, further comprising: a flow control unit comprising a first gas analyzer disposed on the fuel line configured to determine a composition of the fuel stream, a flowmeter disposed on the fuel line configured to determine a volumetric flow rate of the fuel stream, a first control valve disposed on the feed line configured to control a volumetric flow rate of the oxygen-containing stream, a flow controller that is configured to receive a first signal from the first gas analyzer and a flow rate signal from the flowmeter, and to transmit a second output signal to the first control valve, wherein the flow control unit is configured to control the volumetric flow rate of the oxygen-containing stream based on a composition and volumetric flow rate of the fuel stream.
 9. The combustion system of claim 6, further comprising: a recycle line that fluidly connects the exhaust line to the fuel line; and a temperature control unit comprising a temperature sensor disposed on the exhaust line configured to determine a temperature of the exhaust stream, a second control valve disposed on the recycle line configured to control a volumetric flow rate of the exhaust stream, a temperature controller configured to receive a temperature signal from the temperature sensor, and to transmit a third output signal to the second control valve, wherein the temperature control unit is configured to control the temperature of the fuel stream based on the temperature of the exhaust stream.
 10. The combustion system of claim 9, further comprising: a mixer located upstream of the combustor and fluidly connected to the fuel line and the recycle line configured to mix the fuel stream with the exhaust stream.
 11. The combustion system of claim 10, further comprising: an oxygen-depleted line fluidly connected to the first outlet; and a primary heat exchanger disposed on the recycle line and fluidly connected to the oxygen-depleted line, wherein the primary heat exchanger is located downstream of the first outlet and upstream of the mixer, and is configured to heat exchange the exhaust stream with an oxygen-depleted stream that egresses the first outlet.
 12. The combustion system of claim 6, further comprising: an oxygen-depleted line fluidly connected to the first outlet; and a secondary heat exchanger disposed on the feed line and fluidly connected to the oxygen-depleted line, wherein the secondary heat exchanger is located upstream of the first inlet and downstream of the first outlet, and is configured to heat exchange the oxygen-containing stream with an oxygen-depleted stream that egresses the first outlet.
 13. The combustion system of claim 6, further comprising: a condenser located downstream of and fluidly connected to the expander via the exhaust line configured to separate a liquid phase from the exhaust stream.
 14. The combustion system of claim 5, wherein the combustor further comprises: a third concentric cylindrical zone sandwiched between the first and the second concentric cylindrical zones, defining a sweep zone; and a third inlet and a third outlet located in the sweep zone.
 15. The combustion system of claim 14, further comprising: an expander located downstream of and fluidly connected to the second outlet via an exhaust line for expanding an exhaust stream to generate power.
 16. The combustion system of claim 15, further comprising: a recycle line that fluidly connects the exhaust line to the third inlet.
 17. A process for combusting a fuel stream, comprising: combusting the fuel stream with molecular oxygen in the combustion zone of the combustor of claim 4 to form an exhaust stream comprising water vapor and carbon dioxide; delivering an oxygen-containing stream to the first inlet of the combustor, wherein molecular oxygen present in the oxygen-containing stream is transported to the sweep zone through the ion transport membrane; flowing a portion of the exhaust stream into the third inlet of the combustor to sweep the molecular oxygen away from the sweep zone and to form an oxygen-enriched stream; mixing the oxygen-enriched stream with the fuel stream in a mixer to form a combustion mixture; and delivering the combustion mixture to the second inlet of the combustor, wherein the combustion mixture is expanded and/or agitated in the combustion zone via the swirler and is combusted to form the exhaust stream; and repeating the flowing, the mixing, and the delivering.
 18. The process of claim 17, wherein the fuel stream is a syngas stream.
 19. The process of claim 17, further comprising: expanding the exhaust stream in an expander to generate power.
 20. The process of claim 17, further comprising: adjusting an angle of each blade of the swirler based on a composition of the combustion mixture. 